It can probably be rechambered for the even larger .378 (.375") Weatherby, if the action and boltface can handle the larger cartridge - at an even greater cost in self-abuse from the recoil.
That is why there are so many used big magnums F/S, that have "only been shot a few times", and have an almost-full box of ammo to go with them.
If the rifle is nice, AND it can be had cheaply enough, I would rebarrel it to another cartridge liked better, that has the same size case head (300/7mm Mag ?)
.